FRANKFURT (Reuters) - Volkswagen's <VOWG_p.DE> premium carmaker Audi said on Thursday it would recall 4,997 of its A8 model vehicles with V8 diesel engines in Europe to update software after it found they emitted too much nitrogen oxide.

It said it had reported the matter to Germany's motor authority KBA. An Audi spokesman said the KBA was pointing to an illegal manipulation of emissions.

Audi is grappling with car recalls, prosecutor investigations and criticism from unions and managers over the diesel emissions scandal and its performance since news of the affair broke in 2015.

The group said 3,660 of the affected cars were in Germany and were made between September 2013 and August 2017. It said the software would likely be available in the first quarter of 2018.

(Reporting by Maria Sheahan; Additional reporting by Jan Schwartz; Editing by Christoph Steitz)